Lead screw assemblies are well known devices for providing linear actuation. A lead screw assembly converts rotational motion of a lead screw into rectilinear motion of a nut engaging external threads of the lead screw. Over time, the lead screw threads and corresponding threads of the nut will wear resulting in clearance in the engagement of the nut and the screw. This clearance results in reduced accuracy in controlling the motion of the nut and any object connected to the nut. Also, backlash will occur when the lead screw alternates directions of rotation to reverse the linear movement of the nut.
Prior attempts for overcoming backlash in lead screw assemblies are known, for example U.S. Pat. No. 6,467,362 discloses a nut body that includes two nut bodies that are linearly moveable relative to one another and that are wedged apart by a spring biasing a wedge between the two nut bodies. The wedge biases the two nut bodies apart from one another to adjust their relative position to compensate for the wear in the components. In another embodiment embodiment, a coil spring axially biases the two nut bodies apart.
The present invention is directed toward improvements in relation to anti-backlash nuts.